Native source code for Quick Tips episode: Power-Up Your Previews

PowerUpYourPreviewsNative.swift

//
//  PowerUpYourPreviewsNative.swift
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
//  of the Software, and to permit persons to whom the Software is furnished to do so,
//  subject to the following conditions:
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
//  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
//  PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
//  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
//  AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
//  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//  Created by Adam Fordyce on 08/07/2021.
//  Copyright © 2021 Adam Fordyce. All rights reserved.
//

import SwiftUI

struct IncrementControlNative: View {
    
    var min = Int.min
    var max = Int.max
    
    @Binding var counter: Int
    
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            let buttonSize = geo.size.height
            HStack {
                IncrementButton(sfSymbolName: "minus") {
                    if counter > min {
                        counter -= 1
                    }
                }
                .frame(width: buttonSize, height: buttonSize)
                
                Text("\(counter)")
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                
                IncrementButton(sfSymbolName: "plus") {
                    if counter < max {
                        counter += 1
                    }
                }
                .frame(width: buttonSize, height: buttonSize)
            }
            .font(.system(size: geo.size.height * 0.4))
        }
    }
}

private let buttonGradient = LinearGradient(
    gradient: Gradient(colors: [.orange, .red]),
    startPoint: .leading, endPoint: .trailing)

private struct IncrementButton: View {
    
    let sfSymbolName: String
    let handler: () -> ()
    
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            let cornerRadius = geo.size.width * 0.15
            let lineWidth = geo.size.width * 0.05
                Button {
                    handler()
                } label: {
                    Image(systemName: sfSymbolName)
                        .frame(maxWidth: .infinity, maxHeight: .infinity)
                        .background(buttonGradient)
                        .clipShape(RoundedRectangle(cornerRadius: cornerRadius))
                        .overlay(RoundedRectangle(cornerRadius: cornerRadius).stroke(Color.white, lineWidth: lineWidth))
                }
        }
    }
}

struct IncrementControlNative_Previews: PreviewProvider {
    
    struct IncrementControlNative_Harness: View {
        
        @State private var counter = 2
        @State private var counterWithMin = 2
        @State private var counterWithMax = 2
        @State private var counterWithMinMax = 2
        
        var body: some View {
            VStack(spacing: 20) {
                Group {
                    IncrementControlNative(counter: $counter)
                    IncrementControlNative(min: 0, counter: $counterWithMin)
                    IncrementControlNative(max: 5, counter: $counterWithMax)
                    IncrementControlNative(min: 0, max: 5, counter: $counterWithMinMax)
                }
                .frame(width: 250, height: 60)
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity)
            .foregroundColor(.white)
            .background(Color(white: 0.1))
            .ignoresSafeArea()
        }
    }
    
    static var previews: some View {
        IncrementControlNative_Harness()
            .previewDevice("iPhone 12 Pro Max")
            .previewDisplayName("iPhone 12 Pro Max")
    }
}